1. Technical Field
The present invention relates to a cleaning apparatus that cleans a print head of a printing apparatus, which performs printing by ejecting ink, and the printing apparatus, and more particularly, relates to control of a start timing of regular cleaning which is carried out automatically in the printing apparatus.
2. Related Art
According to the related art, ink jet printers have been used as receipt printers of a POS system for convenience stores or the like.
The ink jet printer performs predetermined printing by ejecting ink of an ink cartridge from a print head to receipt paper or the like. According to such an ink jet printer, in order to prevent the viscosity of ink remaining in nozzles of the print head from being increased and to prevent bubbles from penetrating into the inside of the print head from the nozzles, regular cleaning is automatically performed to clean the print head by absorbing the ink from the nozzles of the print head, so that printing is always performed in a proper state.
Further, since a nozzle formation surface of the print head faces the paper while being spaced apart from the paper at a predetermined interval, paper dust, ink or the like may be easily attached to the nozzle formation surface. If the paper dust, ink or the like are attached to the nozzle formation surface, holes of the nozzles may be clogged or the paper may be contaminated due to the ink attached thereto. In order to solve these problems, the regular cleaning is performed to wipe impurities attached to the nozzle formation surface by using an elastic absorption plate, so that a printing operation can be always performed in a proper state.
In general, the regular cleaning is automatically performed after a predetermined time lapses from the previous cleaning. Thus, in a receipt printer employing the ink jet printer, a start timing of the regular cleaning may be reached while a receipt to be provided to a product purchaser is being printed. In such a case, cleaning must be performed after the printing process is primarily performed, or the printing process must be temporarily stopped so that the cleaning can be primarily performed. However, if the cleaning is primarily performed and thus the purchaser has to wait for a predetermined time until the cleaning is completed, the reputation of the convenience store may be adversely affected in terms of service quality. In contrast, if the printing process is primarily performed so that the regular cleaning is delayed, since cleaning is not performed for a long time, the print quality of the receipt or the like may be degraded.
Further, the start timing of the regular cleaning may be reached during the printing process in an ink jet printer serving as an image recording apparatus in which continuous printing is performed, as well as an ink jet printer used in an office and a household (see paragraphs 0002 to 0014 and 0033 to 0072, and FIGS. 4A to 7 of JP-A-2008-68438).
According to patent document 1, in the ink jet printer serving as the image recording apparatus, if the start timing of the regular cleaning for the print head is reached during the printing process, the printing process is temporarily stopped at a proper timing in consideration of the remaining number of papers to be printed and then the cleaning is performed, so that the workability is improved and the print quality is prevented from being degraded. However, in such a case, the printing process is essentially stopped.
In this regard, there has been proposed a scheme for calculating a low print time zone, in which the printing quantity is equal to or less than a predetermined value, from the previous history of a printing operation in such a printing apparatus which uses the ink jet printer such as the receipt printer, and regular cleaning is performed in the low print time zone, so that the regular cleaning is performed at a proper timing corresponding to the operational environment of the printing apparatus while preventing the printing process from overlapping the regular cleaning (see paragraphs 0013 to 0015 and 0042 to 0064, and FIGS. 4 to 10 of JP-A-2007-98706).
However, although the regular cleaning is performed in the low print time zone calculated based on the previous history as disclosed in JP-A-2007-98706, a printing process for printing a receipt or the like may be necessarily performed in the low print time zone under an operational environment in which the printing process for printing the receipt or the like happens irregularly in a convenience store or the like. At this time, if the regular cleaning is performed, the purchaser or the like must wait until the cleaning is completed. Further, in the printing apparatus of a convenience store open 24 hours a day under the operational environment in which the printing process for printing the receipt or the like happens irregularly through the day, the above problem must be solved.